Alright, let's solve this problem step by step. We have 4026 and 7620 and we're adding them together.

Step 1: We'll start by adding the digits 6 & 0 in column 1 and get 6.

Step 2: We'll start by adding the digits 2 & 2 in column 2 and get 4.

Step 3: We'll start by adding the digits 0 & 6 in column 3 and get 6.

Step 4: We'll start by adding the digits 4 & 7 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 4026 + 7620 = 11646.

